Optical fibers can have tips with varying shapes, and these varying shapes may be utilized in a wide variety of settings and applications. Examples of tip shapes include “up” tapers, “down” tapers, convex lenses, concave lenses, spherical ball lenses, diffusers, side-fires, and angled ends. One particular application in which particular tip shapes are useful is in the medical field. For example, ball lens shaped tips can be utilized for materials processing and tissue cutting. Down taper tips can be utilized for tissue ablation.
For tissue ablation, 360 degree near-uniform beam propagation from a tip is required. However, achieving such beam propagation is difficult. For example, optical fibers alone with normal cleaves can only obtain between approximately 5 degree and approximately 40 degree divergent beam radiation. Some tip designs utilized TiO2 flakes in silicon matrices by splicing the matrices to the cleaved optical fiber, but these tips are not all-fiber structures and are relatively expensive. Doric lens diffusers are also not all-fiber structures and cannot obtain 360 degree near-uniform beam propagation.
Accordingly, improved optical fiber assemblies with down taper tips, and improved methods for forming such assemblies, are desired. In particular, methods and assemblies which provide 360 degree near-uniform beam propagation and are inexpensive, all-fiber structures would be advantageous.